Question

所以程序需要动态分配一个足够大的数组来保存用户=定义的测试分数。输入所有分数后，应将数组传递给按升序对其进行排序的函数。应该调用另一个函数来计算平均分数。程序应显示带有适当标题的分数和平均值的排序列表。尽可能使用指针表示法而不是数组表示法。

我遇到的问题是让程序不接受测试分数的负数。

这是代码。

source.cpp

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
void arrSelectSort(float *, int);
void showArrPtr(float *, int);
void showAverage(float, int);
int main()
{
float *scores,              //To dynamically allocate an array
    total = 0.0,            //Accumulator
    average;                //To hold the averge scores
int numScores;              //To hold the number of test scores
                            //Get the number of test scores.
cout << "How many test scores would you like to process?";
cin >> numScores;
//Dynamically allocate an array large enough to hold that many
//test scores
scores = new float[numScores];
if (scores == NULL)
    return 0;
//Get the test score for each test
cout << "Enter the test scores below.\n";
for (int count = 0; count < numScores; count++)
{
    cout << "Test score #" << (count + 1) << ": ";
    cin >> scores[count];
    while (scores <= 0)
    {
        cout << "Zero or negative numbers not accepted.\n";
        cout << "Test Score #" << (count + 1) << ": ";
        cin >> scores[count];
    }
}
//Calculate the total scores
for (int count = 0; count < numScores; count++)
{
    total += scores[count];
}
//sort the elements of the array pointers
arrSelectSort(scores, numScores);
//Will display them in sorted order.
cout << "The test scores in ascending order are: \n";
showArrPtr(scores, numScores);
showAverage(total, numScores);
//Free memory.
delete[] scores;
return 0;
}
void arrSelectSort(float *array, int size)
{
int startScan, minIndex;
float  minElem;
for (startScan = 0; startScan < (size - 1); startScan++)
{
    minIndex = startScan;
    minElem = array[startScan];
    for (int index = startScan + 1; index < size; index++)
    {
        if (array[index]  < minElem)
        {
            minElem = array[index];
            minIndex = index;
        }
    }
    array[minIndex] = array[startScan];
    array[startScan] = minElem;
    }
}
void showArrPtr(float *array, int size)
{
for (int count = 0; count< size; count++)
    cout << array[count] << " ";
cout << endl;
}
void showAverage(float total, int numScores)
{
float average;
//Calculate the average
average = total / numScores;
//Display the results.
cout << fixed << showpoint << setprecision(2);
cout << "Average Score: " << average << endl;
system("pause");
}

修改source.cpp以使用double而不是float

#include <iostream>
#include <iomanip>

using namespace std;
void arrSelectSort(double *, int);
void showArrPtr(double *, int);
double showAverage(double, int);
int main()
{
double *scores,             //To dynamically allocate an array
    total = 0.0,            //Accumulator
    average;                //To hold the averge scores
int numScores;              //To hold the number of test scores
                            //Get the number of test scores.
cout << "How many test scores would you like to process?";
cin >> numScores;
//Dynamically allocate an array large enough to hold that many
//test scores
scores = new double[numScores];
if (scores == NULL)
    return 0;
//Get the test score for each test
cout << "Enter the test scores below.\n";
for (int count = 0; count < numScores; count++)
{
    cout << "Test score #" << (count + 1) << ": ";
    cin >> scores[count];
    while (scores[count] <= 0)
    {
        cout << "Zero or negative numbers not accepted.\n";
        cout << "Test Score #" << (count + 1) << ": ";
        cin >> scores[count];
    }
}
//Calculate the total scores
for (int count = 0; count < numScores; count++)
{
    total += scores[count];
}
//sort the elements of the array pointers
arrSelectSort(scores, numScores);

cout << "The test scores in ascending order are: \n";
showArrPtr(scores, numScores);
showAverage(total, numScores);

delete[] scores;
return 0;
}
void arrSelectSort(double *array, int size)
{
int startScan, minIndex;
double  minElem;
for (startScan = 0; startScan < (size - 1); startScan++)
{
    minIndex = startScan;
    minElem = array[startScan];
    for (int index = startScan + 1; index < size; index++)
    {
        if (array[index]  < minElem)
        {
            minElem = array[index];
            minIndex = index;
        }
    }
    array[minIndex] = array[startScan];
    array[startScan] = minElem;
    }
}
void showArrPtr(double *array, int size)
{
for (int count = 0; count< size; count++)
    cout << array[count] << " ";
cout << endl;
}
double showAverage(double total, int numScores)
{
double average;
//Calculate the average
average = total / numScores;
//Display the results.
cout << fixed << showpoint << setprecision(2);
cout << "Average Score: " << average << endl;
system("pause");
}

错误 - 严重性代码描述项目文件行抑制状态错误C4716＆＃39; showAverage＆＃39;：必须返回值ConsoleApplication9 c：\ users \ kenny \ desktop \ kenny_fepc1.cpp 85
严重性代码描述项目文件行抑制状态警告C4101＆＃39;平均＆＃39;：未引用的本地变量ConsoleApplication9 c：\ users \ kenny \ desktop \ kenny_fepc1.cpp 12

请帮忙解决。谢谢。

Answer 1

您没有检查输入的值：

while (scores <= 0)

应该是

while (scores[count] <= 0)

我想这是作业，你被要求使用c风格的数组。但请注意，使用std::vector会使任务变得非常简单，因为它具有动态大小（您不必处理＆＃34;手动＆＃34;）并且对矢量进行排序是微不足道的。

顺便说一下，我建议你把循环改为

for (int count = 0; count < numScores; count++) {
    scores[count] = -1;
    while (scores[count] <= 0) {
       cout << "Test Score #" << (count + 1) << "(has to be >0) : ";
       cin >> scores[count];
    }
}

当您想要对代码进行更改时，重复代码总是很麻烦。尽量避免使用它（即使它只有两个小行）。

出现您的其他错误，因为您宣布showAverage返回double但没有return。声明它不返回任何内容：

void showAverage(double total, int numScores)

或在函数末尾添加return语句：

return average;

测试分数 - 输入验证

1 个答案: